Allocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.llocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.
Definition of roost. 1  1a : a support on which birds restb : a place where winged animals and especially birds customarily roost. 2  2 : a group of birds roosting together.
A roost is an elevated bar, branch or narrow plank on which chickens perch to sleep. Seeking high spots to spend the night has been part of chicken survival instincts since long before its domestication over 5000 years ago. Chickens arenât all that fast, they lack the prowess to ward off many predators and they are sound sleepers.